1. Technical Field
The present invention relates to a method of cleaning an intermediate transfer belt using a liquid developer and to an image forming apparatus.
2. Related Art
An electrophotographic image forming apparatus (a wet type image forming apparatus) using a liquid developer is known in the art. A developer that is used in the wet type image forming apparatus is formed by suspending solids (toner particles) in an electrical insulating organic solvent (a carrier liquid). In this case, the particle size of the toner particle is a very fine, for example, 2 μm or less and typically, 1 μm or less. Therefore, the wet type image forming apparatus can realize high image quality compared with a dry type image forming apparatus that uses fine toner particles having a size of approximately 7 μm.
The carrier liquid constituting the developer prevents the toner particles having a size of approximately 1 μm from being scattered, charges the toner particles, and uniformly disperses the toner particles. In addition, the carrier liquid enables the toner particles to easily move by an electric field effect during a developing process or a transfer process. As described above, the carrier liquid is a component required during a toner preservation process, a toner feed process, a development process, and a transfer process. However, the carrier liquid may be stuck to a non-image region, and an excess carrier liquid after the development may cause transfer dispersion. For this reason, the carrier liquid is typically removed (squeezed) with respect to the developer on a photosensitive member or an intermediate transfer member. Additionally, in the wet type image forming apparatus, when a secondary transfer belt or an intermediate transfer belt is used, the liquid developer (the carrier liquid and the solids) that is stuck to the surface of the belt is removed by a cleaning blade (for example, see JP-A-2002-189354).
However, since the an extraneous material (the liquid developer) that is cleaned from the intermediate transfer belt is typically subject to carrier removal in the above-described manner, a ratio of the solids is increased, and the solids are stuck to the surface of the intermediate transfer belt like ‘wet powder’. After the transfer to the paper, the carrier liquid is absorbed from the developer that remains on the intermediate transfer belt into the paper. Then, a stronger force is required to perform cleaning due to the increased ratio of the solids. Therefore, as regards a soft belt (having low elasticity), the surface of the belt is deformed by the cleaning blade, which causes damage to the belt.